Anti-reflection nano-structures fabricated on curved surface of glass lens based on metal contact printing lithography

This paper reports the fabrication of subwavelength nano-structures on the curved surface of a glass lens for the purposes of anti-reflection. It utilizes a flexible PDMS mold to transfer metallic patterns to the lens surface which is pre-coated with a polymer layer. Using the transferred metal pattern as an etching mask, nano-structures are directly fabricated on the lens surface by plasma dry-etching processes. A plano/convex lens made of BK-7 glass with a lens diameter of 12.7 mm and a radius of curvature of 25.8 mm is used in this paper. Hexagonally arrayed nano-structures with a truncated conical profile, a center-to-center pitch of 300 nm, and a maximum structure height of 290 nm are experimentally achieved. Measurement results show the optical transmittance is increased by about 2.4% in average for wavelength within visible light spectrum. The directly fabricated nano-structures also exhibit good anti-glaring effects and the potentials for further optical applications.